The publications and other materials used herein to illuminate the background of the invention, and in particular, cases to provide additional details respecting the practice, are incorporated by reference.
Mammalian 17β-Hydroxysteroid dehydrogenases (17β-HSDs) are NAD(H) or NADP(H) dependent enzymes which catalyze—besides other reactions—the final steps in male and female sex hormone biosynthesis. These enzymes convert inactive 17-keto-steroids into their active 17β-hydroxy-forms or catalyze the oxidation of the 17β-hydroxy-forms into the 17-keto-steroids. Because both estrogens and androgens have the highest affinity for their receptors in the 17β-hydroxy form, 17β-HSD enzymes play an essential role in the tissue-selective regulation of the activity of sex steroid hormones.
At present, 10 human members of the 17β-HSD enzyme family have been described (types 1-5, 7, 8, 10, 11 and 12). The human 17β-HSD family members share less than 30% similarity in their primary structure. The 17β-HSDs are expressed in distinct, though in some cases, overlapping patterns. The different types of 17β-HSDs also differ in their substrate and cofactor specificities. In intact cells in culture, the 17β-HSDs catalyze the reaction in a unidirectional way: types 1, 3, 5 and 7 use NADP(H) as a cofactor and catalyze the reductive reaction (activation), while types 2, 4, 8 and 10 catalyze the oxidative reaction (inactivation) using NAD(H) as a cofactor. [see e.g. Labrie et al. (2000) Trends Endocrinol Metab., 11:421-7].
Due to their essential role in the tissue-selective regulation of the activity of sex steroid hormones 17β-HSDs can be involved in the occurrence and development of estrogen-sensitive pathologies (f. ex. breast, ovarian, uterine and endometrium cancers etc.) and androgen-sensitive pathologies (f. ex. prostate cancer, benign prostatic hyperplasia, acne, hirsutism, etc). Furthermore, many types of 17β-HSD have been shown to be involved in the pathogenesis of particular human disorders. For example, 17β-HSD3 is known to be involved in the development of pseudohermaphroditism, the 17β-HSD8 plays a role in polycystic kidney disease and the 17β-HSD4 is related to the occurrence of bifunctional enzyme deficiency. Therefore treatment of sex steroid-sensitive diseases by administration of specific inhibitors of the 17β-HSDs enzymes have been suggested, optionally in combination with potent and specific antiestrogens and antiandrogens [Labrie F et al. (1997) Steroids, 62:148-58].
Due to the fact that each type of 17β-HSD has a selective substrate affinity, directional (reductive or oxidative) activity in intact cells, and a particular tissue distribution, the selectivity of drug action could be achieved by targeting a particular 17β-HSD isozyme. By individual modulation of the particular 17β-HSDs it is possible to influence or even control the local and paracrine concentration of estrogens and androgens in different target tissues.
The best characterized member of the 17β-HSD family is the type 1 17β-HSD [EC 1.1.1.62]. This enzyme could be crystallized in different states of functionality (e.g. with and without ligand and/or co-factor). The 17β-HSD1 catalyzes in vitro the reduction as well as the oxidation between estrone (E1) and estradiol (E2). However, under physiological in vivo conditions the enzyme only catalyzes the reductive reaction from the estrone (E1) to the estradiol (E2). The 17β-HSD1 was found to be expressed in a variety of hormone-dependent tissues, e.g. placenta, mammary gland tissue or uterus and endometrium tissue, respectively. Estradiol itself is, especially in comparison to the significantly less active estrone, a very potent hormone, which regulates the expression of a variety of genes by binding to the nuclear estrogen receptor and plays an essential role in the proliferation and differentiation of the target cell. Physiological as well as pathological cell proliferations can be estradiol dependent. Especially many breast cancer cells are stimulated by a locally raised estradiol concentration. Furthermore, the occurrence or course of benign pathologies such as endometriosis, uterine leiomyomas (fibroids or myomas), adenomyosis, menorrhagia, metrorrhagia and dysmenorrhea is dependent from the existence of significantly high estradiol levels.
Endometriosis is a well-known gynaecological disorder that affects 10 to 15% of women in the reproductive age. It is a benign disease defined as the presence of viable endometrial gland and stroma cells outside the uterine cavity. It is most frequently found in the pelvic area. In women developing endometriosis, the endometrial cells entering the peritoneal cavity by retrograde menstruation (the most likely mechanism) have the capacity to adhere to and invade the peritoneal lining, and are then able to implant and grow. The implants respond to steroid hormones of the menstrual cycle in a similar way as the endometrium in the uterus. The infiltrating lesions and the blood from these lesions which are unable to leave the body cause inflammation of the surrounding tissue. The most common symptoms of endometriosis are dysmenorrhoea, dyspareunia and (chronic) abdominal pain. The occurrence of these symptoms is not related to the extent of the lesions. Some women with severe endometriosis are asymptomatic, while women with mild endometriosis may have severe pain. Endometriosis is found in up to 50% of the women with infertility. However, currently no causal relation has been proven between mild endometriosis and infertility. Moderate to severe endometriosis can cause tubal damage and adhesions leading to infertility. The aims of treatment of endometriosis are pain relief, resolution of the endometriotic tissue and restoration of fertility (if desired). The two common treatments are surgery or anti-inflammatory and/or hormonal therapy or a combination thereof.
Uterine leiomyomas (fibroids or myomas), benign clonal tumours, arise from smooth muscle cells of the human uterus. They are clinically apparent in up to 25% of women and are the single, most common indication for hysterectomy. They cause significant morbidity, including prolonged and heavy menstrual bleeding, pelvic pressure and pain, urinary problems, and, in rare cases, reproductive dysfunction. The pathophysiology of myomas is not well understood. Myomas are found submucosally (beneath the endometrium), intramurally (within the myometrium) and subserosally (projecting out of the serosal compartment of the uterus), but mostly are mixed forms of these 3 different types. The presence of estrogen receptors in leiomyoma cells has been studied by Tamaya et al. [Tamaya et al. (1985) Acta Obstet Gynecol Scand., 64:307-9]. They have shown that the ratios of estrogen receptor compared to progesterone and androgen receptor levels were higher in leiomyomas than in the corresponding normal myometrium. Surgery has long been the main treatment for myomas. Furthermore, medical therapies that have been proposed to treat myomas include administration of a variety of steroids such as the androgenic steroids danazol or gestrinone, GnRH agonists and progestogens, whereby the administration is often associated a variety of serious side-effects.
Everything that has been said above in relation to the treatment of uterine leiomyomas and endometriosis equally applies to other benign gynaecological disorders, notably adenomyosis, functional menorrhagia and metrorrhagia. These benign gynaecological disorders are all estrogen sensitive and are treated in a comparable way as described herein before in relation to uterine leiomyomas and endometriosis. The available pharmaceutical treatments, however, suffer from the same major drawbacks, i.e. they have to be discontinued once the side-effects become more serious than the symptoms to be treated and symptoms reappear after discontinuation of the therapy.
Since the aforementioned malign and benign pathologies are all 17β-estradiol dependent, a reduction of the endogenous 17β-estradiol concentration in the respective tissue will result in an impaired or reduced proliferation of 17β-estradiol cells in said tissues. Therefore, it may be concluded that selective inhibitors of the 17β-HSD1 enzyme are well suited for their use to impair endogenous productions of estrogens, in particular of 17β-estradiol, in myomas, endometriotic, adenomyotic and endometrial tissue. The application of a compound acting as selective inhibitor on the 17β-HSD1 which preferentially catalyzes the reductive reaction will result in a lowered intracellular estradiol-concentration since the reductive conversion of the estrone into the active estradiol is reduced or suppressed. Therefore, reversible or even irreversible inhibitors of the 17β-HSD1 may play a significant role in the prophylaxis and/or treatment of steroid-hormone, in particular 17β-estradiol, dependent disorders or diseases. Furthermore, the reversible or even irreversible inhibitors of the 17β-HSD1 should have no or only pure antagonistic binding activities to the estradiol receptor, in particular to the estrogen receptor a subtype, since agonistic binding of the estrogen receptor would lead to activation and therefore—by regulation of a variety of genes—to the proliferation and differentiation of the target cell. In contrast, antagonists of the estrogen receptor, so called anti-estrogens, bind competitively to the specific receptor protein thus preventing access of endogenous estrogens to their specific binding site. At present it is described in the literature that several malignant disease as breast cancer, prostate carcinoma, ovarian cancer, uterine cancer, endometrial cancer and endometrial hyperplasia may be treated by the administration of a selective 17β-HSD1 inhibitor. Furthermore, a selective 17β-HSD1 inhibitor may be useful for the prevention of the aforementioned hormone-dependent cancers, especially breast cancer.
Several reversible or irreversible inhibitors of the 17β-HSD1 enzyme of steroidal and even non-steroidal origin are already known from the literature. The characteristics of these inhibitory molecules, which mainly have a substrate or cofactor-like core structure, have been reported in the literature [reviewed in: Poirier D. (2003) Curr Med Chem. 10:453-77].
A further well characterized member of the 17β-HSD family is the 17β-HSD type 3 enzyme (17β-HSD3). The 17β-HSD3 has a distinct feature compared to other 17β-HSDs: it is found to be expressed almost exclusively the testis, whereas the other isoenzymes are expressed more widely in several tissues. 17β-HSD3 has a crucial role in androgen biosynthesis. It converts 4-androstene-3,17-one (A) to testosterone (T). The biological significance of the 17β-HSD3 is of undeniable physiological importance. Mutations in the gene for 17β-HSD3 have found to lead to decreased T formation in the fetal testis and consequently to a human intersex disorder termed male pseudohermaphroditism [Geissler W M et al. (1994) Nat Genet., 7:34-9].
With regard to the indication prostate cancer, the primary cancer cells mostly retain their responsiveness to androgens in their regulation of proliferation, differentiation, and programmed cell death for some period. At present, androgen deprivation is the only effective systemic hormonal therapy available for prostate cancer. The development of selective inhibitors against 17β-HSD3 is a new therapeutic approach for the treatment of androgen dependent disease [Labrie et al. (2000) Trends Endocrinol Metab., 11:421-7]. Furthermore, Oefelein et al. reported that the depot GnRH analogue fails, in nearly 20% of cases, to achieve castrate levels of T in men [Oefelein M G & Cornum R (2000) J Urol.; 164:726-9]. In order to improve the response rate to endocrine therapy for men with prostate cancer it may be important to selectively inhibit testicular 17β-HSD3 activity. Besides prostate cancer, many other androgen-sensitive diseases, i.e. diseases whose onset or progress is aided by androgenic activity, may be treated by selectively inhibiting 17β-HSD3 activity. These diseases include but are not limited to benign prostatic hyperplasia, prostatitis, acne, seborrhea, hirsutism, androgenic alopecia, precocious puberty, adrenal hyperplasia, and polycystic ovarian syndrome. Furthermore, considering the fact that 17β-HSD3 is found mainly in the testis, the development of potent inhibitors could be of interest for blocking spermatogenesis and as an anti-fertility agent for males.
Several reversible or irreversible inhibitors of the 17β-HSD3 enzymes of steroidal and even non-steroidal origin are already known from the literature. The characteristics of these inhibitory molecules have been reported in the literature [reviewed in: Poirier D. (2003) Curr Med Chem. 10:453-77]. For example, U.S. Pat. No. 6,541,463 discloses androsterone derived inhibitors for 17β-HSD3. These derivatives have been synthesised by parallel solid- and liquid-phase chemistry and some of these compounds showed 2 to 18-fold higher inhibition activity than that of the natural substrate of the enzyme, A-dione, used itself as a inhibitor. Furthermore, the international patent application WO 01/42181 discloses benzyl-tetralins, the chemical structure of which is related to that of the phytoestrogen biochanin, as 17β-HSD3 inhibitors. Furthermore, international patent applications WO 98/32724, WO 98/30556 and WO 99/12540 disclose tetralone, benzopyrane and benzofuranone derivatives, which have a 17β-HSD inhibitory activity, for the treatment of hormone sensitive diseases.
Microsomal 17β-hydroxysteroid dehydrogenase of human endometrium and placenta (designated 17β-HSD type 2 or 17β-HSD2) was cloned by expression cloning, and found to be equally active using androgens and estrogens as substrates for oxidation [Andersson S. (1995) J. Steroid Biochem. Molec. Biol., 55:533-534]. The recombinant 17β-HSD2 converts the highly active 17β-hydroxysteroids such as estradiol (E2), testosterone (T), and dehydrotestosterone (DHT) to their inactive keto forms. In addition, the 17β-HSD2 can, to a lesser extent, also convert 20β-hydroxyprogesterone (20βP) to progesterone (P). The broad tissue distribution together with the predominant oxidative activity of 17β-HSD2 suggest that the enzyme may play an essential role in the inactivation of highly active 17β-hydroxysteroids, resulting in diminished sex hormone action in target tissues. Dong and colleagues showed significant 17β-HSD2 activity in cultured human osteoblasts and osteoblast-like osteosarcoma cells MG63 and TE85, but not in SaOS-2 [Dong Y et al. (1998) J. Bone Min. Res., 13:1539-1546]. The potential for interconversion of E1 to E2, T to A, and DHT to A by bone cells could therefore represent important mechanism for the local regulation of intracellular ligand supply for the estrogen and androgen receptors in the osteoblasts and other steroid sensitive cells. This modulation of steroid levels may be employed for a wide variety of indications, including the following: for the prevention and treatment of osteoporosis, for the treatment of ovarian cancer, for the treatment of breast cancer, for the treatment of endometrial cancer, for the treatment of endometriosis, for the treatment of prostate cancer and/or for the treatment of androgen-dependent hair-loss.
Several reversible or irreversible inhibitors of the 17β-HSD2 enzymes of steroidal and even non-steroidal origin are already known from the literature. The characteristics of these inhibitory molecules have been reported in the literature [reviewed in: Poirier D. (2003) Curr Med Chem. 10:453-77]. In addition, the international patent application WO 02/26706 discloses 17β-HSD2 inhibitors of non-steroidal origin.
Some thienopyrimidinones derivatives that are described as being useful in therapy have already been disclosed in the literature: The Japanese patent publication JP48042271 B (Yoshitomi Pharmaceutical industries Ltd.) disclose compounds useful as central nervous depressants and anti-inflammatory agents. The U.S. Pat. No. 5,597,823 (Abbott Laboratories, Inc.) describes adrenergic antagonist useful in the treatment of benign prostate hyperplasia. The Japanese patent application JP62132884 (Mitsubishi Chem. Ind. Ltd.) discloses Benzylthienopyrimidinones useful as cardiovascular agents. Manhas et al describe the synthesis and anti-inflammatory activity of some substituted thienopyrimidinones [Manhas M S et al. (1972) J Med Chem. 15(1):106-7]. Gadad et al. describe the synthesis and antihyperlipaemic activity of some 2-aminomethyl-3-aryl-5,6,7,8-tetrahydrobenzo(b)/5,6-dimethylthieno (2,3-d)-pyrimidin-4-ones [Gadad A K et al. (1996) Arzneimittelforschung. 46(10):981-5]. Manjunath et al. describe the synthesis and evaluation of 2-chloromethyl-3-N-substituted arylthieno(2,3-d)pyrimidin-4-ones and derivatives for central nervous system depressant activity [Manjunath K S et al. (1997) Arzneimittelforschung. 47(9):1005-8].
Furthermore, several other Thienopyrimidinones derivatives have been described but were not related to any medical use so far. For example, the compounds (3-Benzyl-7-tert-butyl-4-oxo-3,4,5,6,7,8-hexahydro-benzo[4,5]thieno[2,3-d]pyrimidin-2-yl)-acetic acid methyl ester (CAS reg. no 423749-31-9) and 2,3-Dibenzyl-7-tert-butyl-5,6,7,8-tetrahydro-3H-benzo[4,5]thieno[2,3-d]pyrimidin-4-one (CAS reg. no 372974-51-1) are commercially available.
However, according to the inventors' knowledge none of the already known compounds described above has been described as useful in the treatment and/or prevention of a steroid hormone dependent disease or disorder, particularly a steroid hormone dependent disease or disorder requiring the inhibition of the 17β-hydroxysteroid dehydrogenase (17HSD) type 1, type 2 or type 3 enzyme.
There is a need for the development of compounds that are selectively inhibiting the 17β-HSD1, 17β-HSD3 and/or 17β-HSD2 enzyme, while desirably failing to inhibit substantially other members of the 17β-HSD protein family, or other catalysts of sex steroid degradation or activation. In particular, it is an aim of the present invention to develop selective inhibitors of the 17β-HSD1 enzyme, whereby in addition the compounds have no or only pure antagonistic binding affinities to the estrogen receptor (both subtypes α and β).